Ingersoll Rand 7.5 will not start back when it hits low side have to hit reset

by Tony Wright
(Rockmart Ga 30153)

Ingersoll Rand 7.5 220 single phase I replaced the pressure switch does the same thing.

Ingersoll Rand 7.5 HP compressor
New Ingersoll Rand T-30compressor


Tony, turn off the compressor and open the tank drain to drain all the air out. Close the drain, and start the air compressor?

Does it start OK?

The reset button you refer to, is it on the electrical panel, motor, or on the breaker, or elsewhere?

Please post your response as a comment here so I can follow the thread.



I/R Compressor Blows Breaker an won’t start up

by Billy
(Columbus Ohio)

Hello Bill,
I am having an issue with my older 80 Gallon IR Compressor. The motor has been replaced with a Baldor 5HP Farm Duty Motor, drawing 28amps.

I have run 10 rominex Wire from my GE box to a 220 Outlet I installed in my garage. Total wire run from box is about 35 ft, with another 10′ of 10 ga Rominex wired to a 220 plug directly on the new Condor Pressure Switch to motor.

The breaker is a double pole GE 30 amp.

The compressor does not have an unloader.

The problem is when the compressor starts up, I get an initial 5 second hum, no spinning, and then the breaker trips. Im wondering if I need larger wire and a bigger breaker to cover initial start up of the motor. My question is, if the motor is pulling 28 amps, is that 14 per leg? If so, if the wire is breakered at 30 amps per leg, then the motor at start up would have to be pulling over double is operating amperage in order to blow the breaker correct? That seems like an awful lot of start up amps. I have recheck all of my wiring from the fuse box, to the 220 outlet, the plug to the compressor, the pressure switch and the wiring inside the motor and everything is correct. The only thing I can think of is the amperage at startup exceeding the rating on the wire, but it shouldn’t.

Appreciate any advice you may have.


All motors pull more amps at startup, or inrush.

The humming motor suggests to me that it’s either not getting enough amps or the start capacitor isn’t kicking in to boost the amps and get the motor running.

Can you do a capacitor check to see if it / they are working? See how to test the capacitors on this site. Leave us a comment to let us know what you found, K?


Ingersoll rand will not kick back on on low side

by Tony Wright
(Rockmart Ga 30153)

The compressor is a matco made by ingersoll rand .220 single phase. Replaced pressure switch that did not help.

Tony, if you dump the air and plug the unit back in, will it start OK?

Will the Matco air compressor reach normal cut out pressure and stop normally?

If it does, when it stops, do you see/hear the unloader valve operated?

Any answers as a comment here will help figure out what’s going on with your compressor.

My 5hp 230 volt IR Compressor will not re-start

by Jim
(Waterford, PA, USA)

The 5 hp compressor was bad when I was given the machine. I installed a 3 hp compressor on the 80 gallon tank from a different machine with a bad motor. So now the 5hp 230 volt single phase motor runs the 3hp compressor.

When the tank is empty everything runs just fine – up to pressure and shuts off and I hear the unloader hiss off the head pressure.

Use the air and the motor kicks in and runs at what seems like 1/2 speed for 3 -4 seconds and trips the 20 amp 230 volt breakers.

Had the motor megged out and all looked okay. Had the Capacitor (760 – 840 mohms) checked out and it looked okay. Run the motor by itself and all okay.

I emptied the tank again and same result. The motor does not even get hot when filling the tank.

I replaced the capacitor with a similar size (708 – 850) that was available and the motor kicked out after 3 seconds of 1/2 speed running.

Any ideas ? Hook 2 capacitors in parallel together ? Thanks

Jim, it sounds like it could be a power supply issue to me. Any chance of that?

If the caps are OK, and the motor is fine, then what might trip it out is low power.